[Python-Dev] A new dictionary implementation (original) (raw)

Mark Shannon mark at hotpy.org
Fri Feb 17 14:35:19 CET 2012

On 15/02/12 21:09, Yury Selivanov wrote:

Hello Mark,

First, I've back-ported your patch on python 3.2.2 (which was relatively easy). Almost all tests pass, and those that don't are always failing on my machine if I remember. The patch can be found here: http://goo.gl/nSzzY Then, I compared memory footprint of one of our applications (300,000 LOC) and saw it about 6% less than on vanilla python 3.2.2 (660 MB of reserved process memory compared to 702 MB; Linux Gentoo 64bit) The application is written in heavy OOP style (for instance, ~1000 classes are generated by our ORM on the fly, and there are approximately the same amount of hand-written ones) so I hoped for a much bigger saving. As for the patch itself I found one use-case, where python with the patch behaves differently:: class Foo: def init(self, msg): self.msg = msg f = Foo('123') class str(str): pass print(f.msg) print(getattr(f, str('msg'))) The above snippet works perfectly on vanilla py3.2, but fails on the patched one (even on 3.3 compiled from your 'cpythonnewdict' branch) I'm not sure that it's a valid code, though. If not, then we need to fix some python internals to add exact type check in 'getattr', in the 'operator.getattr', etc. And if it is - your patch needs to be fixed. In any case, I propose to add the above code to the python test-suite, with either expecting a result or an exception.

Your code is valid, the bug is in my code. I've fixed and updated the repository. More tests to be added later.

Cheers, Mark.

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